Email on the contrary has a long history of stability. The first promotional email campaign was sent in 1978 to a total of 400 people, and email has been growing consistently since. Interestingly, the email space itself has evolved from a time where you needed a developer to build an email, to today where tools like Campaign Monitor empower the modern marketer to create and send beautiful branded emails. This shift has put the power of business email into the hands of more people.
Building your email list, unlike building a social media following, is a stable long-term investment that will pay off for many years to come.